This invention relates, in general, to electronics, and more particularly, to electronic components and methods of manufacture.
Electronic components such as piezoresistive pressure sensors typically have passivation films overlying a thin pressure-sensitive diaphragm. While these piezoresistive pressure sensors are used in a wide variety of applications, these sensors still have many sources of error that degrade sensor accuracy. For instance, piezoresistive pressure sensors have thermal hysteresis errors, which can be caused by the thermal hysteresis of stresses within the passivation films. The thermal hysteresis errors are especially troublesome because they cannot be corrected by using additional circuitry. Furthermore, as another example, piezoresistive pressure sensors also suffer from temperature coefficient of offset errors, which can also be caused by the changes in film stress over temperature within the passivation films.
One technique to reduce the detrimental effects of film stress is to improve the quality of the passivation film to eliminate the amount of film stress and its variation with temperature. However, this improvement is both difficult and expensive to implement because many of the sources of stress hysteresis are not known.
Accordingly, a need exists for a manufacturable and cost-effective piezoresistive pressure sensor that is insensitive, or at least less sensitive, to thermal hysteresis errors and temperature coefficient of offset errors due to film stresses. A need also exists for a manufacturable and cost-effective method of manufacturing the piezoresistive pressure sensor.